Complexity of Boolean functions satisfying the propagation criterion (PC), an extended notion of the perfect nonlinearity, is discussed on several computation models. The following topics are investigated: (i) relationships between the unateness and the degree of the PC, (ii) the inversion complexity of perfectly nonlinear Boolean functions, (iii) the formula size of Boolean functions that satisfy the PC of degree 1, (iv) the area-time-square complexity of VLSI circuits computing perfectly nonlinear Boolean functions, (v) the OBDD size perfectly nonlinear Boolean functions.

In this paper, we propose a method to design ternary cellular arrays by using Ternary Decision Diagrams (TDD's). Our cellular array has a rectangular structure composed of ternary switch cells. The ternary functions represented by TDD's are realized by mapping the TDD's to the arrays directly. That is, both the nodes and the edges in the TDD are realized by some sets of the cells. Since TDD's can represent easily multiple-output functions without large memory requirements, our arrays are wuitable for the realization of multiple-output functions. To evaluate our method, we apply our method to some benchmark circuits, and compare our arrays with the ternary PLA's. The experimental results show that our arrays have the advantage for their sizes, especially in the realization of symmetric functions. The results also clarify that the size of our arrays depends on the size of TDD's.

Calls using different media which require different transfer quality will arrive at ATM networks. Therefore it is important to develop a method for allocating network resources efficiently to individual calls by judging admission of calls. Various call admission control schemes have been already proposed, and these schemes assume that users specify values of traffic descriptors when they originate calls. However, it is sometimes difficult for users to specify these values accurately. This paper proposes a new ATM call admission control scheme based on cell transfer state monitoring which does not require that users specify values of traffic descriptors in detail when they originate calls. In this proposed scheme, the acceptance or rejection of calls is judged by comparing the monitored cell transfer state value with a threshold prepared in advance. This threshold must be adjusted according to changes in the characteristics of traffic applied to ATM networks. This is one of the most serious problems in the control scheme based on the monitoring of cell transfer state. Herein, this paper proposes neural network application to the control scheme in order to resolve this problem and improve performance. In principle, the threshold can be adjusted automatically by the self-learning function of the neural network, and the control can be maintained appropriately even if the characteristics of traffic applied to ATM networks change drastically. In this paper, the effectiveness of the application of a neural network is clarified by showing the configuration of this proposed control scheme with the neural network, a method for deciding various parameter values needed to implement this control scheme, and finally the results of a performance evaluation of the control scheme. Inputs required by the neural network are also discussed.

As a first step to develop a system to analyze or recognize patterns contained in mages, it is important to provide a good base representation that can facilitate efficiently the interpretation of such patterns. Since structural features of basic patterns in document images such as characters or tables are horizontal and vertical stroke components, we propose a new expression of document image based on the MCR expression that can express well such features of text and tabular components of an image.

Data communication by using TCP/IP is one of important services on ATM networks. At one approach in traffic control of this service, the dedicated bandwidth for data transfer is not guaranteed and the feedback congestion control to prevent cell loss is performed in the congestion case. However, when a large quantity of data is transferred within a short period, this traffic control cannot be expected to achieve high efficiency. In this case, it is suitable that the dedicated bandwidth is guaranteed by FRP (Fast Reservation Protocol) before the data is transferred. This paper describes that FRP is superior to the feedback congestion control for large size data transmission. Next, it proposes a selectable traffic control which selects adaptively one of the feedback congestion control and FRP.

Board-to-board signal transmission in a rack system is affected by various types of noise. Signal transmission capability is evaluated on the basis of physical construction parameters and signal conditions, such as rise time and amplitude. This paper examines noise in a rack system and shows that the maximum single-ended transmission capability is 100Mbps when pin-type connectors are used with a signal/ground pin assignment ratio of 1/1.

A deterministic pushdown automaton (dpda) having just one stack symbol is called a deterministic restricted one-counter automaton (droca). When it accepts by empty stack, it is called strict. A deterministic one-counter automaton (doca) is a dpda having only one stack symbol, with the exception of a bottom-of-stack marker. The class of languages accepted by strict droca's is a subclass of the class of languages accepted by doca's. Valiant has proved the decidability of the equivalence problem for doca's and the undecidability of the inclusion problem for doca's. Hence the decidablity of the equivalence problem for strict droca's is obvious. In this paper, we present a new direct branching algorithm for checking the inclusion for a pair of languages accepted by strict droca's. Then we show that the worst-case time complexity of our algorithm is polynomial with respect to these automata.

Two types of dynamic termination, latch-type and RC-type, are useful for low-power high-speed chip interconnection where the transmission line is terminated only if the signal is changed. The gate of the termination MOS in the latch-type is driven by a feedback inverter, and that in the RC-type is driven by a differentiating signal through the resistor and capacitor. The power dissipation is 13% for the latch-type, and 11% for the RC-type in a DC termination scheme, and the overshoot is 32% for the latch-type, and 16% for the RC-type in an open scheme, both at a signal amplitude of 2 V. The RC-type is superior for signal swing as low as a 1 V. On the other hand, RC termination requires large capacitance, and thus high power. Diode termination is not effective for a small swing because of the large ON voltage of diodes.

We propose a new concept of network dimensioning, which is based not only on the grade of service but also on profit. In traditional network dimensioning methodology, the number of circuits on links is designed under a cost-minimization concept with grade of service constraints. Recently, telecommunication markets have become very large and competitive; therefore, we believe that a profit viewpoint is now essential. However, it is difficult to calculate profit in almost all the dimensioning methods currently used, because they mainly employ peak-hour traffic data, while profit depends on all the hourly traffic data which contain both peak and off-peak data. In this paper, we propose using all the hourly traffic data in network dimensioning. From these data and telephone charges for each hour, revenues will be estimated. On the other hand, facility costs will be estimated from the number of circuits. Finally, we can estimate profit from the difference between revenues and facility costs. Focusing on both quality and profits in network dimensioning leads to more advanced quality management and quality control in telecommunications networks than with traditional methodology. This paper outlines a dimensioning method based on profit, and describes its properties, some applications of it, and summarizes further studies.

Optical path technology that employs both WDM/FDM and wavelength routing will play a key role in supporting future high bandwidth transport networks. WP/VWP (Wavelength Path/Virtual Wavelength Path) technologies are very effective in realizing optical path networks. In these networks, since photonic wavelengths are scarce resources, the number of wavelengths required to construct the network must be minimized. However, the wavelength assignment problem, minimizing the number of wavelengths, is an NP-complete problem. Solving this problem heuristically is an important issue for designing large-scale WP/VWP based networks that are also practical. To realize optical path networks, we need to develop path accommodation design algorithms that heuristically solve the wavelength assignment problem. This paper proposes novel path accommodation design algorithms for WP/VWP networks that minimize the number of wavelengths required. We numerically elucidate that the numbers of wavelengths required for active WPs and VWPs are almost equal. When link failure restoration is considered, they are different; more wavelengths are needed with the WP scheme than with the VWP scheme. It is also demonstrated that the proposed algorithms are applicable to a large scale network design.

A new gloss-extracting method is proposed in this study. A spatial filter with variable resolution is used for the extraction of glossiness. Various spheres and cylinders with curvature radii from 4 to mm are used as the specimens. In all samples, a strong correlation, with a correlation coefficient of more than 0.98, has been observed between psychological glossiness Gph perceived by the human eye and glossiness Gfm extracted by this method. This method is useful for plane specimens as well as spherical and cylindrical ones.

A problem of obtaining an optimal file transfer on a file transmission net N is to consider how to distribute, with a minimum total cost, copies of a file with some information from a vertex of N to all vertices of N by the respective vertices' copy demand numbers (i.i., needed numbers of copies). The maximum number of copies of file which can be made at a vertex is called the copying number of the vertex. In this paper, we consider as N an arborescence-net with constraints on copying numbers, and give a necessary and sufficient condition for a file transfer to be optimal on N, and furthermore propose an O(n2) algorithm for obtaining an optimal file transfer on N, where n is the number of vertices of N.

In the actual sound environmental systems, it seems to be essentially difficult to exactly evaluate a whole probability distribution form of its response fluctuation, owing to various types of natural, social and human factors. We have reported a unified probability density expression in the standard expansion form of Hermite type orthonormal series taking a well-known Gaussian probability density function (abbr. p.d.f.) as the basis for generally evaluating non-Gaussian, non-linear correlation and/or non-stationary properties of the fluctuation phenomenon. However, in the real sound environment, there still remain many actual problems on the necessity of improving the above standard type probability expression for practical use. First, a central point in this paper is focused on how to find a new probabilistic theory of practically evaluating the variety and complexity of the actual random fluctuations, especially through newly introducing an equvivalence transformation toward the standard type probability expression mentioned above in the expansion form of Hermite type orthonormal series. Then, the effectiveness of the proposed theory has been confirmed experimentally too by applying it to the actual problems on the response probability evaluation of various sound insulation systems in an acoustic room.

The blazing effects of dielectric grating consisting of two adjacent sinusoidally modulated layers which lead to the asymmetric profiles on a substrate are analyzed by using improved Fourier series expansion method. This method can be applied to the wide range of grating structure and gave high accurate results by comparing with those obtained by previous method. In this paper, the efficient blazing effects can be achieved by varying normalized distance (w/p) and the normalized thickness (d1/D), where D is kept fixed. The results are greater than those of trapezoidal profiles and triangular profiles. The influences of the second order of modulation index on the radiation efficiencies and normalized leakage factor are also discussed.

We discuss properties of acyclic graph evolution driven by node-firing. The research background and basic concepts of acyclic graph evolution are from the mutual exclusion problem in distributed environments. We proposed in our previous work a mutual exclusion protocol which is based on the notion of evolution trajectories of acyclic graphs. In this paper, we analyze firing concurrency and periodicity of the acyclic graph evolution, from graph theoretical point of views, and investigate topological conditions for assuring the number of firable nodes below a some fixed constant, at any instance of the evolution trajectory. A marked graph, a subclass of Petri nets, is often utilized as a proof tool in analysis.

A key element in the CDMA transmission is DS spreading. Spreading in a DS/SSMA system are provided in two categories-synchronization and data. For synchronization sequences, good auto-correlation and cross-correlation properties are required in order to guarantee fast acquistion with a minimum false alarm probability. On the other hand, the auto-correlation property may not be so important in data spreading since synchronization is obtained by synchronization spreading. In this paper we provide a set of synchronization sequences and a set of data sequences--each a set of binary N-tuples--that have the necessary correlation constraints.

This paper describes an exact symbolic formulation of resource-constrained scheduling which allows speculative operation execution in arbitrary forward-branching control/data paths. The technique provides a closed-form solution set in which all satisfying schedules are encapsulated in a compressed OBDD-based representation. An iterative construction method is presented along with benchmark results. The experiments demonstrate the ability of the proposed technique to efficiently extract parallelism not explicitly specified in the input description.

We propose a nonlocal impact ionization model applicable for the drain region where electric field increases exponentially. It is expressed as a function of an electric field and a characteristic length which is determined by a thickness of gate oxide and a source/drain junction depth. An analytical substrate current model for n-MOSFET is also derived from the new nonlocal impact ionization model. The model well explains the reason why the theoretical characteristic length differs from empirical expressions used in a pseudo two-dimensional model for MOSFET's. The nonlocal impact ionization model implemented in a device simulator demonstrates that the new model can predict substrate current correctly in the framework of drift-diffusion model.

The paper describes a new algorithm for Boolean matching, which is based on BDD structure manipulation. Pruning of the search space takes place after partial assignments if certain subgraphs of two BDD's become inequivalent. This pruning is different from existing techniques, so that the search space is further reduced. Another feature of this algorithm is topological filtering. Usually, many functions have no matchings and this is easily found by only counting the number of minterms. To check it quickly, upper and lower bounds of minterm count are calculated from topological information. Using these bounds, functions that have no matchings are discarded without building their BDD's.

On mutually coupling lines, the transmission signal is dispersively propagated by crosstalk coupling between lines and shows complex propagation characteristics caused by reciprocal reflections. Usually, the differential equation and the integral equation have been applied to analyze the solutions of transmission lines. In this paper, we propose a different analytical method of the propagation characteristics of signal and crosstalk noise. By setting up crosstalk coupling line as a sectionally divided digital transmission network and by using the signal flow graph and the difference equation, the propagation characteristics in the frequency domain, the space domain and the time domain on mutually coupling lines can be obtained. To verify the validity of this method and analyze the complex propagation problems, we first study the crosstalk characteristics of a twisted pair cable via the third circuit by unidirectional coupling. Subsequently we will analyze the coupling theory of bidirectional coupling lines.